Research continues to point to the impact of the amount of chemicals we are all exposed to throughout a normal day. Although this isn't lost on government agencies, such as the FDA, there is a tendency to evaluate safety at a product level rather than considering the total amount of chemicals we are exposed to through a combination of products and environments.   If you're not careful, your garden can certainly host a number of toxin's. Research from the University of Washington and University of California San Francisco go into to detail in an academic paper entitled Health Effects of Common Home, Lawn, and Garden Pesticides. A quote:

The pediatric health burden of pesticide exposure includes both acute and chronic health impacts. Acute symptoms range from mild and subtle to severe (eg, nausea, headaches, skin rashes, eye irritation, seizures, coma, and death). Chronic conditions associated with pesticides in epidemiologic studies of children include birth defects, cancer, asthma, and neurodevelopmental/neurobehavioral effects.

Scary stuff. Mitigation strategies are available. We pride ourselves in our our ability to help you realize your goals so if if you are concerned about toxins in your environment, we's suggest this item become central in the design process. Designers can create plans that will make use of plants, typically indigenous, that are less vulnerable to pests and delicate conditions, that will require less pesticides and fertilizers. Naturally we select our products carefully but anything that can be done at plan inception to address your needs is clearly the best approach.

For a more general resource on how toxins affect you and your family, go to the Environmental Working Group's website.